• Title/Summary/Keyword: 고유동

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Flexural Behavior of RC Beams made of High Flowing Self-Compacting Concrete with Normal Strength (보통강도 고유동 자기충전 철근 콘크리트 보의 휨거동)

  • Choi, Yun-Wang;Kim, Jee-Sang;Chu, Seok-Beom;Lee, Haeng-Ki;An, Tae-Ho;Ha, Sung-Kug
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.349-352
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    • 2008
  • The research conducts a four-point loading test by making two reinforced concrete beams(HSCC test specimen and conventional concrete test specimen) in order to apply an HSCC with a normal strength(30MPa) to a structure. Also, it compares and analyzes the characteristics of the flexural behavior of HSCC and conventional concrete. The stiffness and ductility of the test specimens of HSCC and conventional concrete show similar behavior, but HSCC is more effective in crack control than conventional concrete. The result of the research demonstrates that HSCC can be applied in the construction site.

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New Method for evaluation the Segregation Resistance of High-Fluidity Concrete (고유동 콘크리트의 새로운 재료분리 저항성 평가방법에 관한 제안)

  • 한천구;김기철
    • Magazine of the Korea Concrete Institute
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    • v.10 no.2
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    • pp.147-154
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    • 1998
  • 고유동 콘크리트의 특성을 판정하기 위한 방법으로서 기존에 알려진 재료분리 판정 방법은 매우 복잡하고 번거로운 실험방법으로 실무 적용에 많은 어려움이 있다. 그런데, 고유동 콘크리트의 유동성 측정 방법에는 슬럼프 플로우를 주로 측정하고, 슬럼프는 변화가 작아서 배제되고 있는 실정이나, 재료분리된 양상을 살펴보면 슬럼프 플로우는 큰 반면, 슬럼프는 작은 양상을 보이고 있다. 따라서 본 연구에서는 고유동 콘크리트의 재료분리 저항성을 슬럼프와 슬럼프 플로우의 조합으로 간단히 평가할 수 있는지 그 가능여부를 검토하고자 하였다. 연구 결과 슬럼프 플로우에 대한 슬럼프의 비는 양호한 재료분리의 평가지표로 이용할 수 있는데, 이 값을 2.5 이하로 유지하면 실무에서의 고유동 콘크리트는 양호한 재료분리 저항성을 관리할 수 있을 것으로 사료된다.

Possibility Analysis on Reducing Formwork Leakage of High-fluidity Mortar by Using PVA and Borax (PVA 및 붕사를 사용한 고유동 모르타르의 거푸집 누출량 저감 가능성 분석)

  • Kim, Young-Ki;Lee, Yu-Jeong;Heo, Jun-Ho;Han, Dongyeop
    • Journal of the Korea Institute of Building Construction
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    • v.22 no.2
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    • pp.125-136
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    • 2022
  • This research is to reduce the formwork leakage of high-fluidity concrete caused by insufficient accuracy of formwork fabrication widely used for high-fluidity concrete to general strength concrete. However, in the actual construction site, because of the insufficient accuracy of formwork fabrication may cause leaking concrete of mortar through a gab of the formwork. Therefore, in this research, which builds on previous research into providing thixotropy with PVA and Borax, the use of thixotropy to reduce high-fluidity mortar leakage was evaluated. The results of the experiment proved that the use of thixotropy with PVA and Borax can contribute to reduction of the formwork leakage of high-fluidity mortar. This finding is expected to lead to further research on reducing leakage of high-fluidity concrete.

Hydration Heat Properties of High Flowing Self-Compacting Concrete with Normal Strength (보통강도 고유동 자기충전 콘크리트의 수화발열 특성)

  • Choi, Yun-Wang;Kim, Byoung-Kwon;Lee, Jae-Nam;Ryu, Deug-Hyun;Song, Yong-Kyu;Jung, Woo-Yong
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.497-500
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    • 2008
  • This research carries out experiments for hydration exothermic rate and adiabatic temperature rise of concrete to examine the characteristics of the hydration heat of high flowing self-compacting concrete with a normal strength. As a result of the hydration exothermic rate experiment, the high flowing self-compacting concrete that used Lime stone powder and fly ash as polymers shows that its hydration heat amount reduces due to the reduction of unit cement. The result measured the adiabatic temperature rise of concrete presents that high flowing self-compacting concrete having lots of binder contents has a good performance in temperature reduction due to the effect of polymer and that triple adding high flowing self-compacting concrete has a similar temperature rise speed with conventional concrete. As a result of the research, high flowing self-compacting concrete shows a better temperature reduction performance for the binder content per unit than conventional concrete. In addition, it is judged that triple adding high flowing self-compacting concrete with a specified concrete strength 30 MPa is more beneficial in temperature reduction and early hydration heat than double adding high flowing self-compacting concrete.

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Durability Characteristics and Environmental Assessment of Controlled tow-Strength Materials Using Bottom Ash (Bottom Ash를 재활용한 저강도 고유동 재료의 내구성 및 환경영향 평가)

  • 원종필;이용수;이존자
    • Journal of the Korea Concrete Institute
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    • v.14 no.2
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    • pp.223-230
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    • 2002
  • The main intent of this research was to determine the feasibility of utilizing recycling bottom ash as CLSM (controlled low-strength material). CLSM is a cementitious material, commonly a blend of portland cement, fly ash, sand, and water, that is usually flowable and self-leveling at the time of placement. The durability characteristics of mixtures made bottom ash we compared with those of fly ash CLSM in order to evaluate the effectiveness and suitability of bottom ash as material in CLSM. A comprehensive evaluation of the bottom ash in CLSM and mix proportions indicated that the bottom ash are capable of performing as CLSM mixtures. The durability characteristic of CLSM incorporating the bottom ash under various physical and chemical causes of deterioration were investigated. Test results indicated that CLSM using bottom ash has acceptable durability performance. CLSM incorporating with bottom ash were also found to be environmentally safe.

Evaluation of Filling Performance of Steel Concrete Panel (SCP) Mock-up Member with Low-binder based High-fluidity Concrete (저분체 기반 고유동 콘크리트의 Steel Concrete Panel Mock-up 부재 충전 성능 평가)

  • Park, Gi Joon;Park, Jung Jun;Kim, Sung Wook
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.39 no.4
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    • pp.477-483
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    • 2019
  • Recently, precast type SCP modules are being used instead of PSC structures in order to reduce the construction period and costs of special structures such as nuclear power plants and LNG storage tanks. The inside of the SCP module is connected with a stud for the integral behavior of the steel and concrete, and the use of high fluidity concrete is required. High fluidity concrete generally has a high content of binder, which leads to an increase in hydration heat and shrinkage, and a problem of non-uniform strength development. Therefore, in this study, fluidity and passing performance of high fluidity concrete according to material properties are investigated to select optimum mix design of low binder based high fluidity concrete. Mechanical properties of high fluidity concrete before and after pumping are examined using pump car. The filling performance of SCP mock-up members was evaluated by using high fluidity concrete finally.

Flowing Characteristic of High Flowing Self-Compacting Concrete with mixing Steel Fiber (강섬유 혼입에 따른 고유동 자기충전 콘크리트의 유동특성)

  • Choi, Yun-Wang;Choi, Wook;Kim, Gi-Beom;Jeong, Jae-Gwon;Ahn, Tae-Ho;Eom, Joo-Han
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.461-464
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    • 2008
  • This study is compactability and Passing ability to get to know the flowing characteristic of high flowing self-compacting concrete with mixing steel fiber of various size and diameter. After flowing test, size and diameter are getting longer, flowing performance is getting lower. It meets the standard of combined high flowing self-compacting concrete of JSCE 2 grade and passing performance from ASTM C 1621. Through this study, it can be possible to be applied in site of HSCC with mixing steel fiber.

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